This application relates to an apparatus and method for monitoring the caloric expenditure rate of a subject, and also for monitoring the caloric diet of the subject.
Good personal health and fitness in general, and weight management in particular, requires some form of monitoring the caloric diet, both the caloric intake and the caloric expenditure. Many monitoring techniques and devices have been proposed, for example as described in U.S. Pat. No. 6,013,009, and the many patents discussed therein, as well as in U.S. Pat. No. 5,891,042.
U.S. Pat. No. 5,891,042 discloses a fitness monitoring device including a body motion detector (e.g. a pedometer) which measures body motion (i.e. physical activity) of the subject, and a heart rate detector which measures the heart rate, and thereby the exertion level of the subject. The device further includes a processor which may process this information according to a plurality of different modes, one of which is a calorie mode, for converting these measurements into caloric expenditure.
U.S. Pat. No. 6,013,009 discloses a heart rate monitoring system which includes a sub-unit utilizing physical activity data (e.g., walking or running) to calculate a rate of calories burned per pound for each test exercise. The calculation is performed using a pre-programmed formula based on statistical data accumulated from several thousand sample adults.
My prior U.S. Pat. Nos. 4,917,108; 5,038,792; 5,178,155; 5,179,958; and 5,836,300, all of which are hereby incorporated by reference, disclose another system for measuring caloric expenditure using indirect calorimetry, by measuring the metabolism of the subject. Such a system includes a respiratory gas analyzer which detects inhalations and exhalations of the subject, analyzes the oxygen consumption, and produces a caloric expenditure rate measurement from the analysis of the oxygen consumption. Such a technique has a number of advantages for measuring caloric expenditure as described in those patents.
An object of the present invention is to provide apparatus and method for monitoring the caloric expenditure rate of a subject which is particularly, but not exclusively, useful with the indirect calorimeter technique described in my above U.S. patents in order to obtain many of the advantages provided by such a technique. Another object of the invention is to provide apparatus and method for monitoring the caloric expenditure rate of a subject, which apparatus and method are more closely tailored to the individual subject, rather than to statistical samples, and therefore are more capable of attaining higher accuracy than previously known techniques, such as described in U.S. Pat. No. 6,013,009.
Another object of the invention is to provide apparatus and method for monitoring the caloric expenditure rate of a subject according to a technique which is more flexible than previously known techniques, since it enables the individual subject to select one or more of a wide variety of exercises the individual wishes to perform and to measure the caloric expenditure rate applicable to the exercise and exercise rate selected by the subject.
According to one aspect of the present invention, there is provided apparatus for monitoring the caloric expenditure rate of a subject, comprising: a caloric expenditure rate detector for detecting and measuring the caloric expenditure rate of the subject; a body activity detector for detecting and measuring the body activity of the subject; and a processor for storing a measured caloric expenditure rate and a concurrently measured body activity for each of a plurality of different body activities and activity rates, to enable each subsequently detected body activity measurement to be converted to the caloric expenditure rate of the respective subject.
According to further features in the preferred embodiment of the invention described below, the processor is programmable to operate in: a test mode, in which the processor measures and stores a caloric expenditure rate for each body activity; and an operational mode, in which the processor converts each subsequently detected body activity measurement to the corresponding caloric expenditure rate stored during the test mode.
As indicated earlier, the apparatus is particularly, but not exclusively, useful in the indirect calorimetry technique for measuring caloric expenditure as described in the above-cited U.S. patents, in which case the caloric expenditure rate detector would be a respiratory gas analyzer which detects inhalations and exhalations of the subject, analyzes the oxygen consumption, and produces said caloric expenditure rate measurement therefrom.
According to still further features in the described preferred embodiment, the body activity detector produces a body activity measurement also when the body of the subject is relatively at rest, to enable a personal correlation factor also to be computed and stored during the test mode corresponding to a relatively at rest body condition of the subject, and to be used in the operational mode for modifying the caloric expenditure rate measured when the subject""s body is relatively at rest.
The body activity detector may detect physical activities of a subject including walking and running at different rates, and/or physical exertions of the subject, e.g. as indicated by the heart rate of the subject.
The body activity detector may comprise a clock and a position detection system such as a global positioning system (GPS). By storing the user""s position and time at intervals along a walking, running or biking route, the user""s speed may be calculated and correlated with previous measurements of caloric expenditure while performing the exercise at various rates to determine the caloric expenditure over the route.
According to another aspect of the present invention, there is provided a method of monitoring the caloric expenditure of a subject, comprising:
A. equipping the subject with: (1) a calorie expenditure rate detector for producing a caloric expenditure rate measurement of the subject, and (2) a body activity detector for producing a body activity measurement of the subject;
B. during a test mode: (1) utilizing the detectors for producing the caloric expenditure rate measurement and the body activity measurement while the subject is undergoing a plurality of different body activities and at different rates, and (2) storing the correlation between the two measurements for each of the body activities; and
C. during an operational mode:
(1) utilizing the body activity detector for producing a body activity measurement;
(2) retrieving the corresponding caloric expenditure rate measurement stored for the respective body activity; and
(3) utilizing the retrieved caloric expenditure rate measurement as the measurement of the caloric expenditure rate in monitoring the caloric expenditure of the subject.
According to a still further aspect of the present invention, there is provided apparatus for monitoring the caloric diet of a subject, comprising:
a caloric expenditure rate detector for detecting and measuring the caloric expenditure rate of a subject;
a body activity detector for detecting and measuring the body activity of the subject; and
a processor for:
(a) processing a measured caloric expenditure rate and a concurrently measured body activity to compute a personal correlation factor for each of a plurality of different body activities;
(b) modifying a subsequently measured body activity by the personal correlation factor to determine the caloric expenditure of the subject at the time the body activity is measured;
(c) integrating the caloric expenditure rate over a period of time to produce a total caloric expenditure; and
(d) producing a balance of the total caloric expenditure minus caloric intake inputted into the apparatus over the period of time.
It will thus be seen that the present invention involves the actual measurement of caloric expenditure rate of a subject simultaneously with the measurement of the subject""s body activity in order to produce a personal correlation factor which may thereafter be used to compute the actual caloric expenditure by that subject to achieve the particular body activity involved when the body activity is measured. Such a technique, therefore, enables attaining high accuracy for the respective subject and is compatible with the exercises selected by the subject.
Further features and advantages of the invention will be apparent from the description below.